Production of beryllium and other metals



Patented May 19, 1931 UNITED STATES PATENT OFFICE HUGH S. COOPER, OF OLEVELAN D, OHIO, ASSIGNOR CR) BERYLLIUM DEVELOPMENT COR- PORATION, A CORPORATION OF DELAWARE PRODUCTION OF BERYLLIUM AND OTHER METALS No Drawing. Application filed December The-invention relates to the production of metals by electrolysis, and it is particularly concerned with processes wherein fused electrolytes are employed. Certain metals which can best be produced by such processes, 'for example beryllium and thorium, are so readily oxidized'that the elevated temperatures necessary to fuse the electrolyte and the finely divided state in which the metal is initially recovered give rise to difiiculties, and the invention comprises measures by which such difficulties are obviated. The invention also includes as one of its features procedure whereby such metals as those referred to may be protected from oxidation while being converted from the comminuted form in which they collect on the cathode to a coherent state;

The invention relates more particularly to the production of beryllium, and it includes a process of making anhydrous and stable beryllium chlorid which is eminently suitable to give metal of high urity when decomposed by electrolysis. Ot er objects and advantages of the invention will be discussed in the following descriptiom In my application Serial No. 713,299, filed May 14, 1924, I have described and claimed a process wherein thorium is prepared by the electrolysis of anhydrous thorium chlorid, free from oxid, inthe presence of a fused electrolyte comprising a chloride of a more electropositive metal, for example an alkali metal .chlorid. I have now demonstrated that certain parts of the procedure described in that application are likewise applicable to the production of other similarly readil oxidizable metals, such as beryllium and tantalum, and it is therefore my purpose to claim herein such parts of the process without restriction to any particular metal.

A specific example illustrating thepreparation of beryllium chlorid in accordance with ,-my invention will now be described. Two hundred and fifty (250) grams of beryllium oxidwas placed in boats of fused silica in a tube of the same material, so arranged that it could be heated from without to about 1000 C. A vessel containing carbon tetrachlorid was connected to one end of the tube, and a 6, 1924. Serial No. 754,446.

supply of chlorin was so connected to the vessel that a regulated flow of chlorin could be caused to bubble through the carbon tetrachlorid and then to pass throu h the heating tube, carrying with it vapor 0 carbon tetrachlorid. The chlorin stream was started and the tube gradually heated to about 500 (1., With-the carbon tetrachlorid vessel at room temperature. At this point the vessel containing the carbon tetrachlorid was heated on 'a water bath to increase the evolution of vapor from the liquid, and the temperature of the tube was gradually raised to about 9t0 C. This temperature and the stream of chlorin and carbon tetrachlorid vapor were continued for 7 hours. About 1000 cc. of carbon tetrachlorid was distilled during the operation.

The beryllium present in the oxid was converted into chlorid which sublimed and was collected in a suitable receiver. In order to render this chlorid, which was pure and anhydrous, less liable to take up moisture from the air, and easier to handle, it was pressed into rods and melted in chlorin, being then allowed to solidify in the melting vessels in an atmosphere of chlorin, thereby forming hard, dense ingots of glassy appearance. The melting operation required a temperature of 450-500 C.

I prefer to carry out the electrolysis of the beryllium chlorid in a metal pot which serves as container for the fused electrolyte and also as cathode. Iron may be used but I prefer nichrome or chrome iron, particularly the latter, because of their greater resistance to oxidation and other corroding influences which are present under the conditions of the process.

Inorder to recover 50 grams of coherent metal, it'is necessary to electrolyze about one- ,half kilo of beryllium chlorid. The bath may consist, for example, of 2.5 kilos more or less of sodium chlorid, and the cathode pot should be large enough to hold such a bath. The pot should be provided with a cover, which may be dome-shaped. In a convenient arrangement of the apparatus, a dome-shaped cover having a small opening near one edge for the introduction of hydrogen during the electrolysis, and a larger hole near its center, is-

used. The anode which is preferably a heavy graphite rod passes throu h the central hole, which also serves for the introduction of the beryllium chlorid. The excess hydrogen together with hydrochloric acid equivalent to the evolved chlorin escapes through the central opening where the hydrogen burns. The electrolysis may be conducted as follows:

The charge of sodium chlorid is laced in the pot and melted and brought to a out 825 C. in any suitable way. The cover and anode are put into place, and the stream of hydrogen started. About 125 grams of beryllium chlorid isthen introduced and a current of about 150 amperes passed. About six volts is required. The decomposition of the initial charge of beryllium requires about 20 minutes and a second charge of the same size is then'added. The remainder of the half-kiloof chlorid is added in two more lots at twenty-minute intervals and the .electrolysis is continued about 35 minutes after the final addition. a

The electric current and the hydrogen are then cut off, the cover and anode removed, and as much of the fused salt as possible is decanted, leaving the beryllium clinging to the inner wall of the pot. vWhen the pot is cold, the residual material is removed from it and is rapidly leached with ice-water until the. metal is free from soluble matter. The metal may then be washed with alcohol, preferably anhydrous, and dried. It is in the form of large bright crystalline plates and spangles, and is quite freefrom oxid and other impurities. v

If the beryllium is heated in this divided ducing conditions until a substantially oxygen-free chloride of beryllium is formed, and collecting and electrolyzing said chloride, all under anhydrous conditions. V y In testimony whereof, I affix my si HUGH S. COO ER.

condition it oxidizes rapidly, and will neither form a regulus nor alloy with other metals present. To bring it into coherent form it is pressed in steel dies under several tons clssure into strong rods, discs or the like.-

en these are heated to about 12001450 C. in a tightly closed crucible under a fused salt,

. such as sodium of barium chlorid, the particles 'of'metal coalesce, and coherent ingots of bright metal can'be produced.

The above described procedure for separating the deposited metal from the fused electrolyte, whereby oxidation of the metal is minimized if not entirely prevented, and the procedure by which the comminuted metal is reduced to coherent form, are applicable to many metals and are therefore claimed broadly in the appended claim. While the various parts of the invention have been described in detail, with specific times, rates, temperatures, etc, it will be understood that these are given only for illustration, and that many variations are possible.

I claim r p The process of making beryllium which comprises heating a beryllium compound in the presence of a chlorinating agent under reature. 

